\(\lim\limits_{x\rightarrow-\infty}\sqrt{3x^2-2x+1}=\lim\limits_{x\rightarrow-\infty}\left(-x\cdot\sqrt{3-\dfrac{2}{x}+\dfrac{1}{x^2}}\right)\)
\(=+\infty\) vì \(\left\{{}\begin{matrix}\lim\limits_{x\rightarrow-\infty}-x=+\infty\\\lim\limits_{x\rightarrow-\infty}\sqrt{3-\dfrac{2}{x}+\dfrac{1}{x^2}}=\sqrt{3}>0\end{matrix}\right.\)